During the past few decades, people have been travelling over longer distances for longer periods, carrying with them larger and heavier suitcases. Lifting and manually carrying luggage at airports, railway stations, hotels or other sites is a task which is generally disliked by travellers. Rental luggage carts are available at certain sites of this kind but the renting process is itself an inconvenience and such carts do not remain with the traveller after leaving the site of rental. In order to mitigate this problem, wheeled luggage carriers which typically have a lightweight and foldable construction to facilitate handling and storage of the device when it is not in use, have been used. An example of such a carrier is shown in FIG. 1.
Such carriers are essentially small hand trucks of the type which have a platform on which the luggage case is rested, a pair of wheels which extend below one edge region of the platform and a handle which extends upward from the edge region. The user grasps and tilts the handle to lift the platform and luggage case upward from the underlying floor or the like and the carrier may then be pulled or pushed to the destination of the case. Such carriers are helpful but are not entirely free of inconveniences of their own. The carrier is not self-stabilized and it is not entirely self-supporting during movement. A person who is pulling or pushing such a carrier must continually exert additional effort in order to hold the carrier at the tilted orientation that enables it to be travelled along the floor or other surface. In the absence of such effort by the user, gravity pivots the carrier until either the platform or the handle itself contacts the floor.
When the luggage case is removed from the carrier the carrier itself becomes essentially still another separate piece of luggage which the traveller must contend with. The instability of such a carrier when it is tilted to the travelling orientation and the pivoting movement which occurs when the handle is released make it unsatisfactory for certain purposes such as for transporting a small child along with a luggage case.
Over the last couple of decades extensive efforts have been made to make the luggage case itself wheelable without the aid of a separate carrier and nowadays the majority of suitcases are wheeled. Wheeled cases generally have wheels at the base/bottom surface of the case that faces downward when the case is in an upright position. Wheeled case designs generally come in one of two configurations. The first has wheels placed at the opposing corners of one or both ends of a narrow side of a conventional rectangular box-type suitcase. When in this orientation, in which the case can be wheeled along, the case is substantially higher than it is wide. An example of this type of wheeled case can be seen in FIG. 2. A pulling device such as, for example, a loop of cord is provided at one upperside end of the case.
The advantages of this arrangement are ease of changing between carrying and rolling the suitcase and potentially being able to roll the suitcase by one's side without obstruction to walking. However the significant disadvantages are difficulty in manoeuvrability due to a long narrow base, instability due to the narrow base and a high centre of gravity that lead to a propensity for the case to topple to one side or the other. Furthermore, the person pulling such a case generally has to lean over/stoop into an awkward posture to reach the pulling device and generally has inadequate stride clearance in choosing to pull the case behind them. Lengthening the pulling device is a poor option since it further compromises steerability and stability. For this reason, some such cases have a widened base. However, widening the base increases the carrying angle and makes hand carrying the case less ergonomic and more laborious.
The second common configuration of wheeled case as shown in FIG. 3a, known as a cart configuration, has wheels mounted to only one side edge of the narrow base with a retractable handle bar built into the case on the same side of the case to facilitate movement of the case. When the handle bar is extended, the unit may be tilted about the wheels and be operated in essentially the same manner as the previously discussed FIG. 1 luggage case carriers. The advantages of this arrangement include better manoeuvrability, stability and improved ergonomics. The retractable handle is generally easy to deploy and the wheels are easily ‘activated’ by inclining the case on the wheels. However, such a design is not self-supporting during transit and requires continuous lifting support from the user to hold it in the in the tilted state. It is thus good for small and light cases but large size and/or heavy suitcases with this design are, in wheeled operation, cumbersome and tiresome to move around due to their considerable size and weight. Indeed, for the elderly and infirm even the smaller and lighter cases with this design may still be a burden and whereas for short transits the burden may be minor, any such burden becomes increasingly irksome the longer the journey, more tiring the environment and more tired the individual is. Thus though this cart configuration of wheeled luggage case is relatively more stable in transit and ergonomic than cases with “wheels on long/narrow surface”; relatively manoeuvreable; and easy to activate it suffers from being not self-supporting during transit and may be strenuous with heavy loads and for long journeys and more difficult to use if the user's hand/arm has arthritis/deformity or other impairment. Stride clearance can also be an issue and vibrations can be transmitted to the hand (felt) during case transit on rough surface (eg. roads). This configuration of wheeled luggage case also do not facilitate piling up other items on the case (small surface area on top, makes whole luggage heavier because the extra load is placed away from the supporting wheels and towards the carrying hand).
A common variant on the above configuration, known as a spinner configuration, has a set of multidirectional wheels on the endwall and normally is wheeled along level on that endwall. This configuration of wheeled luggage case is self-supporting, and thus there is no not need to hold and support the case all the time during travel; it is multi-directional moving/steering and is easy to activate. However, it has a high center of gravity and wheels on short/narrow surface, thus is unstable and topples easily on cornering and uneven terrain. It is also non-ergonomic, thus strain on wrist and arm (eg when bearing a heavy load and traveling on eg carpet or over sloping ground). Again vibrations are transmitted to hand (felt) during case transit on rough surface (eg. road) and again there is difficulty with piling up other items on the case (small surface area on top).
In all of the previous designs the narrow base and high centre of gravity mean that the cases are unstable.
Back in the 1980's, some tried to attach wheels to the broad side of the suitcase where the surface was widest and push (or pull) the case lying on this widest side on the wheels like a trolley (see prior U.S. Pat. No. 6,041,900 Outerrigger Inc.). This provided better stability with a wide base and low centre of gravity. However, there are practical inconveniences with potential damage to the exposed wheels during transfer and storage and difficulty in packing and unpacking with a non-stationary suitcase. Also, stacking up of such cases within, for example, the cargo hold of a plane or coach becomes fraught with difficulty again because the cases cannot be relied upon to stay in place. Some have tried to make the wheels retractable with a holding mechanism, for example a catch or latch, in order to hold the wheel in its extended position during use. An example of this is shown in U.S. Pat. No. 5,407,039 Alper and Trevethick and illustrated in FIG. 3b below.
The multiple retractable wheels of these prior designs are flimsy, cumbersome and inconvenient to activate and retract. Moreover, they make the whole case too heavy for practical purposes. Since the weight of the case is concentrated on the pivotal points and/or support pins of the wheel retraction mechanisms, stronger and heavier materials are generally needed to prevent breakdown of the mechanisms, further adding to the overall weight of the case. In addition, the holding mechanisms are not always able to support the weight of the often heavy luggage for prolonged use which results in failure of the holding mechanism and luggage of this type will often have to be repaired or replaced on a regular basis. In view of these disadvantages, amongst others, the trolley case arrangement failed to take-off and was quickly abandoned.
In a recent substantial improvement to luggage case design we have proposed a luggage case as disclosed in the applicant's co-pending U.S. patent application Ser. No. 10/587,415, filed Feb. 28, 2005, now U.S. Pat. No. 7,748,508, issued Jul. 6, 2010, entitled “Wheeled Luggage Case” below with respect to FIG. 4. This case is adapted to be wheeled in the manner of a trolley and is self-supporting, with a low centre of gravity and wide base, and thus is stable; more maneuverable without toppling and more ergonomic, easier to push (optional use of body weight) than pull load, easy to pile other luggage on case (largest surface area possible for each case, initial stability with low centre of gravity and broad base). However, there is extra weight to the case due to the extra wheel and retraction mechanism and multi-segmented (4 to 5 section) retractable push handle and housing. The steering wheel assembly has a two-step deployment (or one step—but slightly more effort in deployment than ‘cart’ or ‘spinner’). The deployment may be relatively tedious for short travelling distances. The case would also need a separate handle for cart functionality if it were to be given that functionality, adding weight.
There has been a long felt want for luggage which is (1) easily manoeuvrable with good stability and ergonomics and (2) convenient and practical for use. The present invention in its various aspects is directed to overcoming one or more of the problems discussed and may be embodied in cases of a diverse range of materials—eg hard or soft; plastics, fabric or hybrid construction, metal framed or not, a diverse range of shapes and sizes, large or small, and diverse general or specialist uses—eg large suitcases, small carry-on flight cases or even musical instrument and computer cases or the like.